ParabolaHard
Question
The equation of the common tangent to the curves y2 = 8x and yx = - 1 is
Options
A.3y = 9x + 2
B.y = 2x +1
C.2y = x + 8
D.y = x + 2
Solution
Tangent to the curve y2 = 8x is y = mx +
, So, it must satisfy xy = - 1
⇒
⇒
Since, It has equal roots.
∴ D = 0
⇒
4m = 0 ⇒ m3 = 1 ⇒ m = 1
, So, it must satisfy xy = - 1⇒

⇒

Since, It has equal roots.
∴ D = 0
⇒
4m = 0 ⇒ m3 = 1 ⇒ m = 1Create a free account to view solution
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